A - No Communication With Lighting Control Module (LCM)

Pinpoint Test A: No Communication With Lighting Control Module

A1 - Check Circuit 195 (T/W) For Power

- Disconnect lighting control module connector C3.
- Using a voltmeter, measure for voltage at lighting control module connector pin C3-6, circuit 195 (T/W).

Is voltage B+?

YES GO to A5.
NO GO to A2.

A2 - Check Circuit 195 (T/W) For Short To Ground

- Remove fuse 15 (15A) Town Car, fuse 4 (15A) Crown Victoria, Grand Marquis from fuse junction panel.
- Using an ohmmeter connected to ground, measure resistance at lighting control module pin C3-6, circuit 195 (T/W).

Is resistance less than 5 ohms?

YES SERVICE circuit 185 (T/W) for short to ground. REPLACE fuse 15 (15A) Town Car, fuse 4 (15A) Crown Victoria, Grand Marquis. RESTORE vehicle. RETEST system.
NO GO to A3.

A3 - Check Supply To Fuse 4 (15A)

- Remove fuse 15 (15A) Town Car, fuse 4 (15A) Crown Victoria, Grand Marquis from fuse junction panel.
- Using a voltmeter, measure for voltage at fuse input cavity.

Is voltage B+?

YES SERVICE supply to fuse 15 (15A) Town Car, fuse 4 (15A) Crown Victoria, Grand Marquis. RESTORE vehicle. RETEST system.
NO GO to A4.

A4 - Check Circuit 195 (T/W) For Open

- Using an ohmmeter, measure resistance of Circuit 195 (T/W) between lighting control module pin C3-6 and output cavity of fuse.

Is resistance 5 ohms or less?

YES REPLACE fuse 15 (15A) Town Car, fuse 4 (15A) Crown Victoria, Grand Marquis. RESTORE vehicle. RETEST system.
NO SERVICE Circuit 195 (T/W) for open. RESTORE vehicle. RETEST system.

A5 - Check Circuit 54 (LG/Y) For Power

- Disconnect lighting control module (LCM) connector C3.
- Using a voltmeter, measure voltage at lighting control module connector pin C3-11, circuit 54 (LG/Y).

Is voltage B+?

YES GO to A9.
NO GO to A6.

A6 - Check Circuit 54 (LG/Y) For Short To Ground

- Remove fuse 4 (10A) Town Car, fuse 8 (15A) Crown Victoria, Grand Marquis, from fuse junction panel.
- Using an ohmmeter connected to ground, measure resistance at lighting control module pin C3-11, circuit 54 (LG/Y).

Is resistance less than 5 ohms?

YES SERVICE Circuit 54 (LG/Y) for short to ground. REPLACE fuse 4 (10A) Town Car, fuse 8 (15A) Crown Victoria, Grand Marquis.
NO GO to A7.

A7 - Check Supply To Fuse 8 (15A)

- Remove fuse 4 (10A) Town Car, fuse 8 (15A) Crown Victoria, Grand Marquis, from fuse junction panel.
- Using a voltmeter, measure for voltage at fuse input cavity.

Is voltage B+?

YES GO to A8.
NO SERVICE supply to to fuse 4 (10A) Town Car, fuse 8 (15A) Crown Victoria, Grand Marquis. RESTORE vehicle. RETEST system.

A8 - Check Circuit 54 (LG/Y) For Open

- Using an ohmmeter, measure resistance of circuit 54 (LG/Y) between lighting control module pin C3-11 and fuse output cavity.

Is resistance 5 ohms or less?

YES REPLACE to fuse 4 (10A) Town Car, fuse 8 (15A) Crown Victoria, Grand Marquis. RESTORE vehicle. RETEST system.
NO SERVICE Circuit 54 (LG/Y) for open. RESTORE vehicle. RETEST system.

A9 - Check Logic Ground For Open

- Using an ohmmeter connected to ground, measure resistance at lighting control module pin C3-9, circuit 676 (PK/0) Town Car or circuit 57 (BK) Crown Victoria, Grand Marquis.

Is resistance less than 5 ohms?

YES GO to Computers and Control Systems to diagnose network concern. Information Bus
NO SERVICE Circuit 676 (PK/O) Town Car or circuit 57 (BK) Crown Victoria, Grand Marquis for open. RESTORE vehicle. RETEST system.